Nonexperimental designs
• Description is one level of scientific inquiry
– Remember
• Description
• Prediction
• Explanation
– useful for describing human behavior
• but does not allow for prediction
• does not allow for causal inference
– valuable techniques for certain situations
• When you cannot run an experimental design
• Before we get into specific descriptive methods
we need to discuss a couple of concepts that are
important for evaluating any research
methodology
• Those concepts are
– internal validity
– external validity
– quantitative approaches
– qualitative approaches
Internal validity
• Internal validity
– The degree to which a research design allows
us to form causal relationships
– experimental methods tend to be high
– nonexperimental methods tend to be low
external validity
• external validity (generalizability)
– Do the findings from a research project
generalize to people in real world settings?
• nonexperimental descriptive approaches tend to
be higher
– often done with humans
– often done in real world settings.
• Experimental/laboratory methods tend to be low
– Contrived laboratory settings
– Animal research
• Thus,
– nonexperimental methods tend to be high in
external validity, but low in internal validity.
• Studying children born to mothers that used
cocaine during pregnancy
– Experimental methods tend to be high in
internal validity, but low in external validity
• Studying neonatal rat pups exposed to cocaine.
• research designs can also be described as
primarily qualitative or primarily
quantitative.
– qualitative
• Written descriptions.
• Expressed in nonnumerical terms.
– quantitative
• Data is expressed numerically
• The designs we will discuss in this section are
nonexperimental and their goal is to describe.
• Tend to be low in internal validity, but higher in
external validity.
• Also tend to rely on qualitative data
• We will discuss four approaches
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phenomenology
case studies
field studies
survey research
• Phenomenology
– Similar to Wundt and Titchener’s introspection.
– A description of one’s own immediate experience
• Not a scientific method
– not publicly observable
• Nevertheless has been used as a first step in
developing research questions
– Purkinje
• Purkinje shift (1825)
– noticed that the brightness of colors changed at the
end of the day as the sun was going down
– day
• reds and yellows appeared brighter than blues and greens
– twilight
• blues and greens appeared brighter than reds and yellows
• duplex theory of vision
– cones
– rods
• benefits of phenomenology
– can lead us to new hypotheses and discoveries
– can be useful technique to ask participants about the
study after they get done.
• how the felt about the study
– bored?
– difficult?
• problem with phenomenology
– not public (private experience)
• difficult to know if others would have the same experience
– therefore any observations would have to be verified
with a scientific method.
• Case studies or case history
• A descriptive record of an individuals
experiences and/or behaviors kept by an
outside observer
• Clinical psychologists often use case
studies
• Kazdin (1992) has argued that case
studies serve five major purposes
– 1) They are a source of inferences,
hypotheses, and theories
• The dopamine hypothesis of schizophrenia was
developed from medical case studies
– drugs that worked for psychosis caused Parkinson’s
symptoms
• 2) Source for developing therapy
techniques
– try a new therapy and document its
performance
• doesn’t constitute hard evidence that it is effective
• that would require control groups
• 3) They allow the study of rare
phenomena
– Luria (1968)
• the mind of a mnemonist
– H. M. (surgery in 1953)
• 4) They provide exceptions, or counter
instances, to accepted ideas theories or
practices
– Gazziniga (1972) Split brain patients
• we tend to believe that we have one unified consciousness
• there is evidence that the two hemispheres represent
separate consciousness that cooperate
– corpus callosum
• reach in bag
• touch object with right hand – can tell you what it is
– right hand goes to left brain
• touch with left hand – can’t reply verbally, but can point to
correct
• 5) they have persuasive and motivational
value
– Endel Tulving (forms of memory)
• Episodic, Semantic,Procedural
– H. M.
• Drawbacks of case studies
– When it is a rare disorder it is difficult to know if others
will show similar effects
• small N
– When we rely on self report people may leave things
out that they don’t think are important or are
embarrassed about.
– when they rely on retrospective data (memory)
information can be inaccurate
• people may not remember well
• memories can be altered or reconstructed
– by the way questions are asked.
• Field studies
– naturalistic observation
– systematic observation
– participant observer studies
– naturalistic observation
• Jane Goodall – Chimps
• Gans (1962)
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studied people living in slums
watched people
listened to conversations
attended meetings
• found people were opposed to having the old
buildings replaced
• Naturalistic observation requires the
researcher to be as unobtrusive as
possible.
• It is also primarily a qualitative method
• Of course watching people in natural
settings leads to high rates of external
validity.
• But with no manipulation of variables the
internal validity is low.
• Systematic observation is a more
quantitative approach to naturalistic
observation
• the researcher creates a prearranged
strategy for recording observations.
• The observations are recorded using
specific rules
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Bakeman and Brownlee (1980)
social behavior in children
Videotaped three year olds playing together
taped for 100 minutes
– observers viewed the tape and recorded behavior every 15 seconds
according to the following criteria
• 1) unoccupied: child is not doing anything in particular or is simply watching
other children
• 2) solitary play: Child plays alone with toys, but is uninterested in or
affected by the activities of other children
• 3) together: child is with other children bus in not occupied with any
particular activity
• 4) parallel play: child plays beside other children with similar toys but does
not play with others
• 5) group play: child plays with other children, including sharing toys, or
participating in organized play activities as part of a group of children.
• Type a number into the computer 1-5 every 15
seconds.
– now you have quantitative data
– which activity occurred the most?
– what order do activities occur in? Bakeman and
Brownlee noted the sequence of play activities
• children rarely went from being unoccupied to
group play
• often went from parallel to group play
• perhaps parallel play is a transitional state.
• participant observer studies
– This is a form of naturalistic observation in which the
researched pretends to be a member of the group
they are studying
• Jane Goodall...and chimps might be an example.
– Humphreys (1970)
• befriended gay men that were meeting and having sexual
encounters in public restrooms
– served as a lookout
– but was really collecting data
• even wrote down license plate numbers, obtained addresses,
disguised himself, and visited their homes to interview them.
– unethical
• Methodological issues for all forms of field
studies
• Reactivity
– The presence of an observer may effect
behavior
• unobtrusive measures
– one way mirror
– hidden camera
– 90 degree lens --- eyebrow arch
• Reliability
– the degree to which a measure is stable or consistent
• inter-rater reliability
• two people must score the data
– if the scores are very similar you have a reliable measure
• requires clear operational definitions
• don’t make things too complicated
– my Master’s project
» 6 chambers
» turning, twitching, locomotion, rearing, yawning, locomotion
against wall.
• Survey Research
– rather than simply observing you directly
question your participants about their
behavior, attitudes, beliefs, and intentions
• past, present, or future
– two major considerations
• sampling technique
• construction of questionnaire
• population vs. sample
• Surveys are concerned with external validity.
– does the data reflect how the population actually feels
– to ensure that it does the sample has to be
representative
• convenience
• simple random sampling
• stratified sampling
– form subgroups and sample randomly from each
» Freshman, sophomores, juniors, seniors
• proportionate sampling
– form subgroups and sample randomly, but only as
many in each group as is in actual population
• freshman (31), sophomore (25), junior (14), senior (19), other
(11)
• cluster sampling
– usually used with bigger populations
• randomly select courses to be sampled
• everyone in course would get the survey
– better example might be school districts in Indiana.
– every individual in district gets surveyed if selected.
• open ended vs. closed ended questions
• open ended
– what do you think of parking on IPFWs campus
• closed ended
– How difficult is it to find a parking spot on IPFWs campus
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a) easy – parking is readily available
b) somewhat easy – some days I have to look for a while
c) difficult – most days I have to look for a while
d) very difficult – Every day I spend a significant amount of time
looking for a spot
– likert scale
• On a scale of 1-7 with 1 being very easy and 7 being nearly
impossible how would you rate the ease at which you can find a
parking space on IPFWs campus
– 1...2...3....4...5....6....7